In recent months, Iran's Revolutionary Guard forces have clashed with Kurdish insurgents in northwestern Iran. The rebels are believed to be linked to Turkey's separatist Kurdistan Workers Party (PKK), which is the target of a large-scale operation in southeast Turkey.

The government of Iraq's Kurdish region has come under pressure from Turkey and the United States to deal with Turkish Kurd guerillas who launch attacks into Turkey from bases in northern Iraq.

The PKK has been fighting for autonomy in Turkey's mainly Kurdish southeast since 1984. The violence has killed more than 30,000 people.

The U.S., Turkey and the European Union classify the PKK as a terrorist group.